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    Typescript Randomizer

    A tool to create random data by requested types. It's designed to minimize the arrange phase of unit tests to maximize maintainability, making it easier to create objects containing random test data. So now we don't need for hand-coding anonymous variables as part of a test's arrange phase.

    Randomizer can help by creating variables with random data. Here's a simple example:

    // types
    class Entity {
      id: string;
      name: string;
    interface Response<T> {
      data: T;
    // test
    it('some test', () => {
      const response = Randomizer.create<Response<Entity>>();
      // someClass returns the response data
      const result = someClass.getEntityResult(response);


    Typescript Randomizer includes two parts:

    • Typescript transformer to generate a description for requested types.
    • Randomizer class with methods to create random data according to generated description.

    How to install

    Randomizer doesn't work without the typescript transformer. The transformer needs to be provided at compile time. There are many different ways to do it. Please read the following guide to find your configuration

    Also, there are some ready examples:

    Example usage

    Create random data

    const data = Randomizer.create<string>();
    // "850eb858-f3b7-4d9c-9715-563a7fbd8f0d"

    Create many random data

    interface A {
        a: string;
    const data = Randomizer.createMany<A>(2);
    // [
    //    { a: "dbb04326-3f0d-4eb1-8bec-2b22fef39f0b" },
    //    { a: "3d48ee0b-2004-4745-8453-98b36d260fc4" },
    // ]

    Create random data with default values

    interaface A {
    const data =<A>()
        .with(x => x.a = 'my string')
    // { a: "my string" }

    Create data for types with type arguments

    interface B<C, D> {
        c: C[],
        d: D;
    class A<T> {
        a: B<T, boolean>
    const data = Randomizer.create<A<string>>();
    // {
    //   "a":{
    //      "c":[
    //         "850eb858-f3b7-4d9c-9715-563a7fbd8f0d",
    //         "dbb04326-3f0d-4eb1-8bec-2b22fef39f0b",
    //         "10efb53e-a76f-4b34-83b5-b7cf9a913e46",
    //         "3d48ee0b-2004-4745-8453-98b36d260fc4",
    //         "11774a70-488c-48d5-bb80-b367ecd857ed"
    //      ],
    //      "d":true
    //   }
    // }

    For more examples, take a look for tests folder


    This project is licensed under the MIT License


    npm i ts-randomizer

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